Arrangement and method for identifying fingerprints

ABSTRACT

Arrangement and method for identifying fingerprints, including at least one fingerprint sensor and at least two electrodes, wherein a fingerprint can be detected by the sensor. A first electrode is arranged in the vicinity of a hand support surface at a distance from the support surface such that when a finger is placed on the support surface, the thumb can be placed on the first electrode. At least one second electrode is arranged on the support surface such that at least one finger can be placed on the second electrode. The sensor and the first electrode and/or the at least one second electrode are each designed as one unit. Electric signals are transmitted to the hand via the electrodes by a measuring unit for applying and analyzing the electric signals, and the changes of the electric signals are detected. An identification result is ascertained using the detected fingerprints and signals.

CROSS-REFERENCE TO RELATED APPLICATION

This application is the U.S. national phase of PCT Application No.PCT/EP2015/058742 filed on Apr. 22, 2015, which claims priority to ATPatent Application No. A50300/2014 filed on Apr. 23, 2014, and DE PatentApplication No. 10 2014 008 160.5 the disclosures of which areincorporated in their entirety by reference herein.

TECHNICAL FIELD

The present invention relates to an arrangement for identifyingfingerprints, comprising at least one fingerprint sensor and at leasttwo electrodes, wherein it is possible to detect a fingerprint with thefingerprint sensor. Furthermore, the invention relates to an associatedmethod for identifying fingerprints.

PRIOR ART

These days, fingerprint sensors are used in entry authorization systemssuch as turnstiles, entry barriers, etc. or in access authorizationsystems for identifying persons and hence for checking entry and/oraccess authorizations. Furthermore, fingerprint sensors may also be usedin mobile devices such as e.g. smartphones, laptops, tablet PCs, etc. inorder, for example, to check authorizations in respect of use of thesedevices or to restrict access to these devices to one or more authorizedpersons. In particular, fingerprint sensors may also find use in gamesand/or amusement and/or gaming machines, as are used in casinos oramusement arcades, or they can be used in devices actuated by money ormonetary value (e.g. vending machines for selling e.g. wares or gamingchips) for identification purposes and for checking authorizations, etc.

Within the scope of the respective use, the fingerprint sensor usuallyserves for user identification, wherein a fingerprint sensor reads ordetects biometric data, such as e.g. a print of a thumb or of afingertip of a person by optical or electrical—usually capacitive—means.The detected biometric data or fingerprints can then be used in variousways. By way of example, a release apparatus connectable to thefingerprint sensor may, depending on the detected fingerprint, e.g.clear a device function, allow access to a respective device or lift adevice block or allow entry to a region or release an entry barrier ifthe detected fingerprint corresponds to a stored fingerprint or comessufficiently close to the latter. Conversely, if there is a sufficientlylarge deviation of a detected fingerprint from stored fingerprints, itis possible, for example, to deny entry, access or the use of a device.Particularly in the case of games and/or amusement and/or gamingmachines, or in the case of mobile devices such as e.g. smartphones,tablet PCs, laptops, etc., it is possible to check whether an authorizedor barred or non-authorized person attempts to actuate or use therespective device with the aid of the fingerprint.

An essential precondition for identifying persons or for checkingauthorizations is the protection against fakes. In particular, it isnecessary to prevent non-authorized persons from obtaining entry, accessor use authorizations for devices etc. by means of e.g. reproducedfingers, cut off fingers or fake fingerprints which, for example, areapplied to the fingers by means of a film. Therefore, together with thefingerprint, it is essential also to carry out a check as to whether theperson with this fingerprint is alive or whether, possibly, e.g. a filmwith fake fingerprints has been adhesively bonded to the fingers inorder to simulate the corresponding authorizations. For so-calleddetection of life, it is possible, for example, to apply various methodsfor electronic person identification, by means of which it is possible,in addition to recording a fingerprint, to determine whether theassociated person is alive. To this end, it is possible to record e.g. apulse frequency or electrocardiographic signals or e.g. measure a skintemperature, mechanical properties of the skin surface, blood pressure,etc.

Document EP 0 853 795 B1 has disclosed a fingerprint sensor withdetector for detection of life, in which an impedance measurement of afingertip placed onto the fingerprint sensor is carried out. To thisend, two point electrodes are provided on the bearing surface of thesensor, said electrodes having a strip-shaped embodiment and a meshingarrangement.

Then, a permittivity is measured at different frequencies of an appliedvoltage with the aid of these electrodes which lie very close together.However, the in document EP 0 853 795 B1 has a relatively complex setupof the electrodes. Furthermore, on account of the relatively smalldistance between the electrodes, measurement errors and/or faultymeasurements, which may have to be repeated where appropriate, mayeasily occur, for example in the case of inaccurate positioning, in thecase of slight movements of the placed finger or as a result of dirt onthe sensor.

Document EP 1 094 750 B1 describes a method for detecting living humanskin, in which a region of a skin surface, such as e.g. a fingertip, isbrought into contact with one or two mutually insulated electricalconductors, where an electrical potential of a superposition offrequencies from a predetermined interval is applied. By way of example,the one electrical conductor or the two electrical conductors may beattached in a bearing surface for taking up a fingerprint. Initially, areference characteristic is recorded for each person to be identified bymeans of the electrical conductor, said reference characteristicreproducing a frequency dependence of an ohmic resistance or an absolutemagnitude of an impedance. This reference characteristic is then usedfor the detection of life for comparison with a recorded characteristicof the person to be identified. That is to say, in addition to e.g. afingerprint, a reference characteristic for determining life is alsorecorded for each person to be identified. This leads to a relativelycomplicated registration method, in which it is necessary to record andstore not only the fingerprint but also a reference characteristic or atleast selected impedance values for the reference characteristic in apredetermined AC voltage frequency range.

Document WO 2010/051041 describes an apparatus and a method foridentifying fake fingerprints, wherein prints of individual fingers or aplurality of fingers, or of relatively large areas of skin, arerecorded. To this end, a plurality of electrodes are arranged in thebearing surface for the fingers in the apparatus. These electrodesprovide electrical signals and a determination as to whether therecorded finger or fingers are real or not is then carried out on thebasis of detected electrical signals, for example by determining theelectrical impedance. However, the electrodes may be arranged in anyconfiguration (e.g. as an electrode field, assigned to specific fingers,etc.) on the bearing surface, with a group of electrodes arranged atright angles being provided for each finger to be recorded whenrecording a plurality of fingers and each one of the fingers to berecorded being checked for authenticity. However, this leads to arelatively complex setup of the apparatus and much outlay whenidentifying fake fingerprints since each finger is checked in respect ofauthenticity by means of a dedicated electrode group. Furthermore, itmay be difficult for the user to position the fingers on the respectiveelectrode groups and an incorrect or inexact placement of the fingersmay lead to measurement errors and/or incorrect measurements.

SUMMARY OF THE INVENTION

Therefore, the present invention is based on the object of specifying anarrangement and a method of the type set forth at the outset, by meansof which the disadvantages of the prior art are avoided and the latteris ultimately developed in an advantageous manner—in particular, thereliability when identifying fingerprints should be increased and anerror susceptibility should be reduced by simple handling in a simplemanner and without a complicated setup.

According to the invention, the object is achieved by an arrangement anda method of the type set forth at the outset, having the features of theindependent claims. Advantageous embodiments of the present inventionare described in the dependent claims.

According to the invention, the object is achieved by an arrangement ofthe type set forth at the outset, in which a first electrode is arrangedspaced apart from a hand bearing surface in the vicinity of said handbearing surface in such a way that, when index finger and/or middlefinger and/or ring finger and/or little finger of a hand is placed ontothis hand bearing surface, the thumb of this hand is able to be placedagainst the first electrode. The first electrode may therefore also beable to be denoted as a thumb electrode. Furthermore, at least onesecond electrode is attached to the hand bearing surface in such a waythat at least one finger selected from index finger, middle finger, ringfinger or little finger is able to be placed onto at least the secondelectrode. The at least one second electrode may also be referred to asfinger electrode. A fingerprint sensor, by means of which a fingerprintis detectable, and the first electrode and/or the at least one secondelectrode are embodied as a unit. That is to say, a fingerprint sensormay be assigned either to the first electrode or to the at least onesecond electrode, said fingerprint sensor then being able to detect aprint of the respective finger (e.g. thumb or index finger), or onefingerprint sensor is in each case assigned to the at least twoelectrodes (i.e. first and at least second electrode), with prints ofe.g. at least two fingers (e.g. thumb and index finger) being detectablein this case. Furthermore, the arrangement comprises a measurement unitfor applying and evaluating electrical signals between the at least twoelectrodes. Here, the electrodes are coupled to the measurement unit bymeans of mutually electrically separated lines. By means of thearrangement, an identification result is established in a simple manner,said identification result e.g. possibly consisting of a fingerprintdetected by the fingerprint sensor and signals detected by themeasurement unit.

The main aspect of the arrangement for identifying fingerprints consistsof simpler handling by the user being made possible by the arrangementof first electrode and the at least one second electrode and theassignment of a fingerprint sensor to at least one of the twoelectrodes, and hence of incorrect measurements and/or repetitions ofmeasurements being reduced. The first electrode, which may e.g. beembodied as a unit with the fingerprint sensor, is arranged next to thehand bearing surface such that a thumb extending away from said handbearing surface comes to rest, with the tip of the thumb, on the firstelectrode or on a unit made of fingerprint sensor and first electrode.If the remaining fingers of the same hand are placed onto the handbearing surface, at least one of the remaining fingers is applied to theat least one second electrode, with the fingerprint sensor being able tobe assigned to the at least one second electrode, or form a unit withthe latter, as an alternative to the first electrode.

Optionally, it is also possible for one fingerprint sensor to beassigned to the at least two electrodes in each case; thus, e.g. theidentification of a user may be improved and e.g. an error rate may bereduced in a simple manner as prints from at least two fingers may beused for the identification. By way of example, in addition to a printof the thumb, which is detectable by e.g. a unit made of first electrodeand fingerprint sensor, it is also possible to detect a print of afurther finger (e.g. of the index finger) by a further unit made of afurther fingerprint sensor and the at least one second electrode. Then,if one of the detected fingerprints does not have an acceptable quality,use can be made, e.g., of the at least one further, detected fingerprintand the user may be identified in the case of appropriate quality. Thismay also avoid, or at least reduce, repetitions of measurements and/orthe detection of fingerprints.

In the present invention, the spacing between the first electrode andthe hand bearing surface is advantageously restricted to the usual thumbreach of a hand of average size.

Hence, correct positioning of thumb and remaining fingers for theidentification is therefore intuitive and simple for the user, as aresult of which measurement errors and/or incorrect measurements arealso reduced. Hence, the identification of the fingerprint, including adetection of life, may be carried out with little time outlay and thereliability of e.g. checks for user clearance, entry and/or accessauthorizations may be increased.

It is advantageous if the hand bearing surface is configured as ahandle, which is able to be grasped by the index finger and/or middlefinger and/or ring finger and/or little finger of the hand. By graspingthe handle, the user is intuitively led to correct positioning of thethumb and remaining fingers for identifying the fingerprint. By graspingthe handle, at least one finger selected from index finger, middlefinger, ring finger and little finger is automatically placed onto theat least second electrode. In the process, the thumb extending away fromthe grasped handle will—virtually by itself (on account of the handgeometry)—come to rest on the first electrode or the unit made offingerprint sensor and first electrode, with the first electrode beingable to be attached directly next to—i.e. within usual thumb reach of ahand of average size—the handle or else directly on the handle on a sideof the handle facing the user.

In accordance with a further aspect of the present invention, the handbearing surface may be provided on a device housing side—e.g. whenapplying the arrangement in a mobile device (e.g. a smartphone, a tabletPC, etc.) or in an amusement device or gaming machine.

This device housing side is arranged in an inclined manner in relationto a further device housing side, wherein the the first electrode or theunit made of fingerprint sensor and first electrode is attached to thefurther device housing side. In particular, the two housing sides, onwhich firstly the aforementioned hand bearing surface and secondly thefirst electrode or the unit made of fingerprint sensor and firstelectrode are arranged, may be aligned at approximately right angles inrelation to one another. The handling for the user is very simple inthis development of the invention as well. By way of example, while thestretched fingers of a hand rest on the one device housing side and thesecond electrode is contacted by at least one of the fingers, the thumbmay, in a natural position so to speak, grip around a housing cornerand, so to speak, rest on the first electrode or the unit made offingerprint sensor and first electrode around the housing edge.

However, particularly when applying the arrangement in a mobile devicesuch as e.g. a smartphone, a tablet PC, etc., the first electrode or theunit made of fingerprint sensor and first electrode may also be attachedto a device housing front side—i.e. on that device housing side whichhas e.g. a display, operating buttons, etc. The hand bearing surfacewith the second electrode may then be arranged e.g. on the devicehousing rear side such that, when the mobile device is picked up in thehand, the thumb, in a natural position so to speak, may be positioned onthe first electrode or the unit made of fingerprint sensor and firstelectrode on the front side of the device and the remaining fingers ofthe hand, likewise in a natural position so to speak, may be positionedon the hand bearing surface and hence on the second electrode on therear side of the device. In the advantageous application of thearrangement in a mobile device, a fingerprint sensor may also beassigned either to the first electrode or the at least one secondelectrode, or both the first and the at least one second electrode mayeach form a unit with one fingerprint sensor.

In order to be able to appropriately use the arrangement equally wellfor the left hand and the right hand, the first electrode or the unitmade of fingerprint sensor and first electrode may in each case beattached symmetrically in relation to a central axis of the hand bearingsurface. Thus, in the case of a hand bearing surface embodied as ahorizontal handle, for example, a first electrode may be attached to theleft-hand side and a further electrode may be attached, like the firstelectrode, spaced apart on the right-hand side in the vicinity of thishandle. Hence, the arrangement can be used very easily with both theleft hand and the right hand. If a fingerprint sensor is integrated intothe first or thumb electrodes arranged to the left and to the right ofthe hand bearing surface in each case, an identification of thefingerprints is able to be carried out in a simple manner with both theleft hand and the right hand.

However, alternatively, a hand bearing surface appropriately adapted tothe respective hand may be also be arranged symmetrically in relation toa central axis of the first electrode in each case. That is to say, forexample, a first hand bearing surface may be used with the left-hand,with the thumb of this hand coming to rest on the first electrode. Byway of example, a hand bearing surface arranged in a manner mirrored inthe central axis of the first electrode may be used with the right hand.When index finger, middle finger, ring finger, and little finger areplaced onto the second hand bearing surface, the thumb of the right handis intuitively, or automatically, placed onto the first electrode.

In an advantageous development of the invention, the first electrode isnot arranged or aligned rigidly in a fixed position relative to the handbearing surface but instead it is movably arranged or movably mounted inorder to be able to be brought into individual positions, i.e. positionsappropriate for the respective user and his hand. Here, the firstelectrode may ideally be mounted in e.g. a rotatable and/or tiltableand/or translationally displaceable manner.

By way of example, the first electrode may be mounted in a mannerrotatable or tiltable about at least one axis of rotation, whereinprovision may be made for tiltability about a tilt axis which is alignedat least approximately perpendicular to the bearing surface of the firstelectrode or of the fingerprint sensor if, for example, the latter formsa unit with the first electrode, and/or about a tilt axis which isaligned at least approximately parallel to a plane in which the bearingsurface of the first electrode or of the fingerprint sensor, if thelatter is e.g. assigned to the first electrode, lies or to the plane towhich the bearing surface nestles. By way of example, when arranged onan upright device housing side, the first electrode may be tiltableabout an upright tilt axis and/or tiltable or rotatable about ahorizontal tilt axis which extends parallel to the upright devicehousing side on which the first electrode is arranged. As an alternativeor in addition to the aforementioned upright and horizontal tilt axes,the first electrode may also be tiltable or rotatable about ahorizontally extending tilt axis which is substantially perpendicular tothe device housing side on which the first electrode is arranged.

As an alternative or in addition to such a tiltability or rotatability,the first electrode or a unit made of fingerprint sensor and firstelectrode, if the fingerprint sensor is e.g. assigned to the firstelectrode, may also be mounted in a translationally displaceable manner,in particular in a plane approximately parallel to the device housingside on which the first electrode or the unit made of fingerprint sensorand first electrode is provided. By way of example, the first electrodeor the unit made of fingerprint sensor and first electrode, if thefingerprint sensor forms a unit with the first electrode, may bedisplaceable upward and downward and/or left and right on an uprightdevice housing front side in order to be in an ideal position relativeto the hand bearing surface for the further fingers. If the firstelectrode is arranged on a horizontally aligned device housing side, thefirst electrode or the unit made of fingerprint sensor and firstelectrode, if the fingerprint sensor forms a unit with the firstelectrode, may be displaceable to the right and left and/or forward andbackward.

It is furthermore expedient if the first electrode and the at least onesecond electrode is produced from a light-transmissive material. As aresult, the respective electrode—i.e. the first electrode or the atleast one second electrode or the at least two electrodes—can easilyform a unit with a respective fingerprint sensor without interferingwith, or impairing, the functionality of the latter or the detection offingerprints. By way of example, the respective electrode may be appliedon the respectively provided fingerprint sensor. Furthermore, thisallows a determination of life to be carried out approximately parallelwith the detection of a fingerprint by the fingerprint sensor, orimmediately after the detection.

Ideally, the at least one second electrode may also comprise a further,i.e. second, fingerprint sensor. As a result, it is possible to detectat least one further print of a further finger in addition to the printof the thumb which is detectable by the unit made of fingerprint sensorand first electrode. In this way, for example, the identification of auser is improved and, for example, an error rate is reduced since printsof at least two fingers may be used for the identification. By way ofexample, if a detected fingerprint does not have an acceptable quality,use can be made of e.g. the at least second, detected fingerprint andthe user may be identified in the case of appropriate quality. As aresult, it is also possible to avoid, or at least reduce, repetitions ofmeasurements and/or the detection of fingerprints.

In an advantageous development of the invention, the at least one secondelectrode is embodied as a force-effect detection unit, in particular ase.g. a pressure switch or pressure sensor. Here, the electrical signalsare only appliable to the respective electrode, or able to be tapped orevaluated, by the measurement unit in the case of force exerted onto theforce-effect detection unit by the appropriate finger. Optionally, thefirst electrode may also be embodied as a force-effect detection unit.By embodying the at least second electrode as a force-effect detectionunit, the fingerprint is only identified once a force is applied to thecontact surface by the corresponding finger applied to the secondelectrode. By way of example, the force-effect detection unit may bebased on a spring-force restoration and embodied as a pressure switch.Alternatively, use can be made of e.g. a force-measuring, electricalresistor such as e.g. a so-called force-sensing resistor (FSR) and theforce-effect detection unit may therefore be embodied as a pressuresensor. Applying or tapping and evaluating electrical signals to/fromthe electrodes only takes place when, for example, a pressure thresholdor a threshold of the electrical resistance has been reached. As aresult, the reliability of the arrangement in relation to manipulationis additionally increased since, for example, such a force applicationis not readily possible with an entirely artificial finger or anentirely artificial hand, onto which fingerprints have been applied formanipulation purposes.

Ideally, the arrangement is able to be used in a device such as e.g. anamusement device or a gaming machine in order, for example, to easily,quickly and reliably check the identity and authorizations of a user.Occasionally, a bearing surface for the fingers of an open hand, i.e.index finger, middle finger, ring finger and/or little finger, isprovided on gaming machines or other devices of the type set forth atthe outset such that the user of the device may place the open hand onthe aforementioned bearing surface. By selecting a suitable distancebetween the hand bearing surface, in particular the handle, with the atleast one second electrode and the first electrode, it is possible, inan advantageous manner, to realize—indirectly—an age restriction whenthe arrangement is used in a gaming or amusement device. Here, thedistance between the hand bearing surface and the first electrode isdimensioned for e.g. for a mean thumb length of a hand of an adult,preferably 60 to 80 mm. As a result, e.g. children or adolescents arethen no longer able to place the thumb on the first electrode when thehand is placed onto the hand bearing surface or when the handle isgrasped because the distance is too large. Consequently, the e.g. devicecannot be put into operation as a result thereof.

Furthermore, operating buttons may be provided on the bearingsurface—such as e.g. a pressure switch or a rocker switch, by means ofwhich device functions are controllable. Here, for example, the at leastone second electrode may be integrated into the respective operatingbutton or attached to the latter. Furthermore, such a bearing surfacemay be provided on a horizontal housing portion such as e.g. ahorizontally aligned keyboard portion. Alternatively, such a bearingsurface for the stretched fingers of a hand may also be arranged on anupright side surface, for example in order to be able to actuate theflippers on a pinball machine, on which the actuation buttons for theflippers are attached laterally on the right and on the left.

The first electrode and the aforementioned hand bearing surface with theat least second electrode, with a fingerprint sensor being assigned toat least one of the at least two electrodes, and the measurement unitmay be arranged immediately on/in the device housing of the gamingmachine or main device. However, in an alternative development of theinvention, the device having the first electrode, the fingerprint sensorassigned to at least one of the electrodes and the hand bearing surfacemay be embodied as a separate input device as well, in which e.g. themeasurement unit is also arranged and which has an interface forconnection to the main device, e.g. in the form of a gaming machine or aPC. The aforementioned interface may e.g. comprise a serial interface,for example embodied in the form of a USB interface or a LAN or WLANinterface.

Furthermore, the arrangement may advantageously also be employable in amobile device, such as a smartphone or tablet PC, in order, for example,to protect these from use or access by unauthorized persons. The firstelectrode or the unit made of fingerprint sensor and first electrode mayin this case be attached to e.g. a device housing front side which, forexample, comprises display, operating buttons, etc. Ideally, the firstelectrode or the unit made of fingerprint sensor and first electrode isintegrated into an operating button (e.g. on/off switch, etc.) orattached to the latter. The hand bearing surface with the at leastsecond electrode may, for example, be arranged on one of the sidesurfaces of the mobile device or on the device housing rear side.Alternatively, or additionally, the hand bearing surface with the secondelectrode may, however, also be applied to a device protective sleeve—aso-called cover—e.g. laterally or on the rear side thereof and, forexample, be contacted through, or electrically connected, to the mobiledevice. Optionally, the device protective sleeve may also have acorresponding cutout such that an application of index finger and/ormiddle finger and/or ring finger and/or little finger onto the at leastone second electrode is easily possible. By providing appropriatecutouts in the device protective sleeve, the user can furthermore easilybe instructed to such an extent that the fingers are placedautomatically onto the at least one second electrode.

The specified object is furthermore solved by a method of the type setforth at the outset, in which the arrangement according to the inventionis used, said arrangement having at least one fingerprint sensor and atleast two electrodes and a measurement unit, wherein a unit is formed bythe fingerprint sensor and a first electrode or by the fingerprintsensor and an at least second electrode or respectively one fingerprintsensor is assigned to both the first electrode and the at least onesecond electrode and hence at least two units made of electrode andfingerprint sensor are formed. For the purposes of identifying afingerprint, the thumb of one hand is placed on the first electrode andat least one further finger selected from index finger, middle finger,ring finger or little finger is placed on the at least one secondelectrode, wherein a fingerprint sensor is assigned to at least one ofthe electrodes. Here, the at least one second electrode is attached to ahand bearing surface which is arranged in the neighborhood—ideallywithin the usual thumb reach of a hand of average size—at a distancefrom the first electrode. A fingerprint is detected by the fingerprintsensor—for example in an optical or electrical—usually capacitive—manneror by means of ultrasound imaging. By way of the first electrode and theat least one second electrode, electrical signals are transferred to thehand applied by way of the thumb and fingers and the measurement unitthen detects and evaluates the electrical signals modified by the handapplied to the electrodes. Here, an identification result is establishedon the basis of the detected fingerprint and the electrical signalsdetected by the measurement unit.

The main aspect of the method for identifying fingerprints consists ofit being possible, in a simple manner and almost in one step, to detecta fingerprint of a user and to carry out a so-called lifedetection—i.e., a check is carried out as to whether the detectedfingerprint originates from a living person. The user is guided to acorrect position for the fingerprint identification by simple handling,i.e., in particular, by the defined hand bearing surface, as a result ofwhich it is possible to reduce error-afflicted measurements and/orrepetitions of measurements. Hence, the identification of thefingerprint, including a determination of life, may therefore be carriedout with little time outlay and the reliability of e.g. checks for usageclearances, entry and/or access authorizations can be increased.

Here, it is advantageous if a detected fingerprint is forwarded to anoverarching system such as e.g. a computer system, in which e.g.fingerprints of authorized persons are stored. Then, an evaluation andanalysis of the detected fingerprint may be carried out in thisoverarching system. By way of example, a check can be carried out as towhether a detected image of a fingerprint has sufficiently acceptablequality for the evaluation. A lack of quality may arise as a result ofe.g. an image contrast that is too low, a detection of an insufficientregion of the fingerprint or an insufficient number of so-calledminutiae points of the fingerprint. The detection of the fingerprint maybe repeated in the case of an insufficient quality of the fingerprintimage. If the detected fingerprint image has sufficient quality for theevaluation and analysis, it may be processed further by the overarchingsystem in order to assist the electrical analysis of wrong orcounterfeit fingerprints.

An expedient development of the invention provides for the modifiedelectrical signals, detected by the measurement unit by way of theelectrodes, to be compared with a predetermined region, in particularfor the determination of life, by the measurement unit. What isestablished here is whether the detected, electrical signals lay e.g.within specific thresholds of a specific person which were recorded andstored during e.g. a registration phase of this person or whether theycorrespond, in general, with thresholds for a human. If the detected,electrical signals lie within the specific or general thresholds orwithin the predetermined range for the detection of life, the detectedfinger or the associated fingerprint is accepted as real or genuine. Ifa deviation from the predetermined region or the thresholds isdetermined, the detected finger is e.g. declared a fake.

Expediently, an imitation value may be created by the measurement uniton the basis of a comparison of the detected, electrical signals withthe predetermined range and e.g. output and/or forwarded by themeasurement unit to the overarching system for evaluation and analysis.By way of the imitation value, the identified finger or the detected,electrical signals may be classified with a probability for a fake (e.g.reproduced finger with an applied fingerprint, cut-off finger, etc.).Then, a high or low probability for an imitated or so-called fake fingermay be derived, for example on the basis of a level of the imitationvalue (e.g.

number of points, numerical value, etc.). With the aid of theoverarching system, a decision can then be made on the basis of theimitation value as to whether e.g. the finger is accepted as real orevaluated as faked.

Voltage signals with a variable amplitude and/or frequency are ideallyused as electrical signals which are transferred by the electrodes tothe applied fingers. By way of example, such voltage signals can veryeasily be generated with the aid of a direct current (DC) voltage oralternating current (AC) voltage signal source (e.g. pulsed DC currentsource, signal generator, etc.). By way of example, such signal sourcesmay be integrated into the measurement unit or embodied separatelytherefrom. The signals may be guided to one or more electrodes by way oflines, by means of which the electrodes are coupled to e.g. themeasurement unit and/or the signal source. Ideally, the lines, by meansof which the individual electrodes are coupled to the measurement unitand/or the signal source, are electrically insulated from one anothersuch that the electrical signals from/to the individual electrodes donot influence one another and possibly lead to measurement errors. Inaccordance with a further embodiment, the electrodes may partly beconnected as an ESD protection for dissipating electrostatic chargesand, in part, be provided for an impedance measurement and be connectedto the measurement unit.

In an advantageous development of the invention, at least the at leastone second electrode is embodied as a force-effect detection unit. Onlyin the case of a force exerted by the appropriate finger onto theforce-effect detection unit are the electrical signals applied to therespective electrode by the measurement unit. Tapping or evaluating theelectrical signals modified by the fingers applied to the electrodes isonly carried out when a predetermined threshold for the exerted force onthe force-effect detection unit is exceeded. Optionally, the firstelectrode may also be embodied as force-effect detection unit.

By way of example, the force-effect detection unit may be based onspring force restoration and may be configured as a pressure switch.Then, a spring pressure threshold is advantageously predetermined asthreshold for the force-effect detection unit. Alternatively, use can bemade of e.g. a force-measuring, electrical resistor such as e.g. aso-called force-sensing resistor (FSR) and the force-effect detectionunit may therefore be embodied as a pressure sensor. That is to say, apassive component, which operates as a variable electrical resistor andwhich changes or reduces the resistance value thereof e.g. withincreasing force on the sensor, is used in the force-effect detectionunit configured as a pressure sensor. Applying or tapping or evaluatingthe electrical signals at the electrodes then only takes place once thecorresponding threshold—e.g. a pressure threshold or threshold of theelectrical resistance—is reached or exceeded. Furthermore, provision canbe made of an indication apparatus (e.g. LED, etc.), by means of whichreaching of the corresponding threshold of the force-effect detectionunit is indicated, e.g. by lighting up, a color change, etc. Hence, theuser is provided with feedback that a further exertion of force on theforce-effect detection unit is no longer necessary.

The security in relation to manipulation may be additionally increasedin a simple manner by the configuration of at least the second electrodeas a force-effect unit. This is because a corresponding action of forceis not readily realizable e.g. with an imitated, artificial finger (e.g.rubber finger) or an imitated hand (e.g. rubber hand), onto whichfingerprints were applied for manipulation purposes.

IMPLEMENTATION OF THE INVENTION

The invention is explained in more detail below on the basis ofpreferred exemplary embodiments and associated drawings. In thedrawings:

FIG. 1: shows an overall view of a device in the form of a gaming and/oramusement machine, which comprises screens and a horizontally alignedoperating panel with input means, wherein an embodiment according to theprior art is depicted, in which a fingerprint sensor is providedcentrally on a top side of the operating panel,

FIG. 2: shows a schematic top view of the top side of a device housingportion, wherein the arrangement for identifying fingerprints accordingto the invention is attached to the device housing,

FIG. 3: shows a schematic top view of a device housing portion similarto FIG. 2 with the arrangement for identifying fingerprints according tothe invention, wherein the hand bearing surface is configured as ahandle which is grasped by the fingers of a hand,

FIG. 4: shows a perspective front view of the device housing portionfrom FIG. 3, which shows, in an exemplary manner, a positioning of thearrangement according to the invention on the device housing front sideand a positioning of a unit made of a fingerprint sensor and firstelectrode relative to the hand bearing surface,

FIG. 5: shows a schematic view of a rear side of a hand bearing surfacefrom FIG. 3 or FIG. 4, configured as a handle,

FIG. 6: schematically shows a side view of a mobile device, inparticular a smartphone, in which the arrangement for identifyingfingerprints according to the invention is used,

FIG. 7: shows a schematic overall view of a mobile device, in particulara smartphone, in which the arrangement for identifying fingerprintsaccording to the invention is used, and

FIG. 8: shows a sequence of the method for identifying fingerprints withthe arrangement according to the invention in a schematic and exemplarymanner.

By way of example, the invention may be used in a device 1—asschematically depicted in FIG. 1—for identifying fingerprints. By way ofexample, the device 1 depicted in FIG. 1 may be embodied as a gamingand/or amusement machine, as used in casinos or arcades. By way ofexample, the device 1 may be embodied as a standalone device and maycomprise a device housing 2 which—loosely speaking—may have anapproximately cubic shape, but else a sculpture-like design. One or morescreens 3 may be arranged on the device housing 2, but provision mayalso be made of different indication means, such as e.g. rotating reels.

A device housing portion 4, which advantageously may have a horizontalalignment and, for example, be formed in a panel-like manner, may act asoperating portion, wherein input means, for example in the form ofoperating buttons or touchscreen elements, may be provided at theaforementioned device housing portion 4. While a fingerprint sensor 5was arranged centrally on a top side of the aforementioned devicehousing portion 4 with a slight inclination in devices 1 from the priorart, as shown in FIG. 1, the arrangement for identifying fingerprintsaccording to the invention has a special attachment or arrangement inaccordance with the exemplary embodiments of the invention, which areshown in FIGS. 2 to 5.

As shown in FIGS. 2 to 4, the aforementioned device housing portion 4,which, when considered in the entirety thereof, may have a horizontalalignment, may comprise a hand bearing surface 7, it being possible forthe latter e.g. to be arranged horizontally on a first device housingside 9 which e.g. may form a horizontal top side 9 of the device housingportion 4. A first electrode 23 and e.g. a fingerprint sensor 21assigned to the first electrode 23 are attached at a distance from thehand bearing surface 7, with the first electrode 23 and the fingerprintsensor 21 being configured as a unit 6. Here, the first electrode 23 ofthe unit 6 made of fingerprint sensor 21 and first electrode 23 isproduced from e.g. light-transmissive material (indium oxide (In₂O₃:Sn),zinc oxide (ZnO:Al, ZnO:Ga, ZnO:Ti), tin oxide (SnO₂:F, SnO₂:Sb,SnO₂:Ta) or titanium oxide (TiO₂:Nb)) which is at least partlytransparent to a querying light beam. Here, the unit 6 made offingerprint sensor 21 and first electrode 23 may be arranged e.g. on asecond device housing side 10 which may be inclined, in particulararranged approximately perpendicular or aligned approximately at rightangles, to the aforementioned first device housing side 9. Inparticular, the unit 6 made of fingerprint sensor 21 and first electrode23 may be provided on an upright front side 9 of the device housingportion 4. The unit 6 made of fingerprint sensor 21 and first electrode23 is, in this case, at a distance from the hand bearing surface 7 forthe fingers, in particular such that—as depicted in an exemplary mannerin FIG. 3—a thumb 12 of a hand 20 intuitively comes to rest in a naturalposition on the unit 6 made of fingerprint sensor 21 and first electrode23, with the index to little fingers of said hand, in intended use,resting on the hand bearing surface 7. Here, the unit 6 made offingerprint sensor 21 and first electrode 23 may be advantageouslyarranged in a rotatable or tiltable manner. (The corresponding tilt axes13, 14, 16 and 17 are plotted in FIGS. 3 and 4).

The hand bearing surface 7 depicted in FIG. 2 in an exemplary manner maye.g. be contoured in the form of a slight depression in order tointuitively guide the hand 20 into the correct position. By way ofexample, an input means, e.g. in the form of an operating button, bymeans of which e.g. control commands for the device 1 may be entered,may be assigned to the hand bearing surface 7. Attached to the handbearing surface 7 is at least one second electrode 8, on which at leastone finger selected from index finger, middle finger, ring finger orlittle finger is able to be placed on the at least second electrode 8.By way of example, the at least one second electrode 8 may be integratedinto an input means assigned to the hand bearing surface 7 or it may beattached thereon. The at least one second electrode 8 may have thefingerprint sensor 21 instead of the first electrode 23. That is to say,the fingerprint sensor 21 may form a unit 6 with the at least secondelectrode 8 instead of with the first electrode 23 or the thumbelectrode 23. Then, a print of a different finger—e.g. of the indexfinger—is recorded instead of a print of the thumb 12, said new printthen being used for identification purposes. Alternatively, the at leastsecond electrode 8 may likewise have a further fingerprint sensor 21 inaddition to the first electrode 23. This means that at least one furtherfingerprint of a further finger (e.g. of the index finger) of the hand20 is recorded in addition to the print of the thumb 12 for moreaccurate identification purposes. The at least second electrode 8is—particularly if a fingerprint sensor 21 is assigned thereto—ideallyproduced from light-transmissive material as well.

Furthermore, provision is made—not depicted in FIGS. 2 to 4—of ameasurement unit 25 (cf. FIG. 8), by means of which electrical signalsmay be applied and evaluated between the first electrode 23 and the atleast second electrode 8 of the hand bearing surface 7. Here, anidentification result is able to be established on the basis of thedetected fingerprint by means of the unit 6 made of fingerprint sensor21 and first electrode 23 and on the basis of the detected signals.Furthermore, the at least second electrode 8 attached to the handbearing surface 7 may be embodied as a force-effect detection unit.Optionally, the first electrode 23 may also be configured as aforce-effect detection unit. By embodying at least the second electrode8 as a force-effect detection unit, the electrical signals of themeasurement unit 25 are only able to be applied or tapped/evaluated inthe case of a force exerted by the corresponding finger onto theforce-effect detection unit.

Alternatively, when viewed in the entirety thereof, the aforementioneddevice housing portion 4 may also have an upright alignment. Here, thehand bearing surface 7 on e.g. a (lateral) vertical device housing sideand the unit 6 made of fingerprint sensor 21 and first electrode 23 on avertical front side may be arranged spaced apart from one another insuch a way that, when the fingers of the hand 20 are applied to the handbearing surface 7, the thumb 12 once again intuitively comes to rest onthe unit 6 made of fingerprint sensor 21 and first electrode 23. Atleast one finger selected from index finger, middle finger, ring fingeror little finger is placed on the at least second electrode 8 when thehand 20 is applied to the hand bearing surface 7, as a result of whichit is possible to establish an identification result from the detectedfingerprint and from signals detected by means of the measurement unit25. The device housing side with the hand bearing surface 7 maypreferably be arranged in an inclined fashion in relation to theaforementioned device housing side with the unit 6 (made of fingerprintsensor 21 and first electrode 23) or the hand bearing surface 7 and theunit 6 may be situated on two different planes, said planes having anangle in relation to one another such that the thumb 12 of the hand maybe placed comfortably onto the unit 6 when at least one finger selectedfrom index finger, middle finger, ring finger or little finger of thishand is placed on the hand bearing surface 7. An intersection of the twoaforementioned planes may in this case lie parallel to a housing edge(preferably a front side facing an operator side).

As depicted in an exemplary manner in FIGS. 3 to 5, the hand bearingsurface 7 may also be configured as a handle 7. By way of example, thehandle 7 may be embodied in the form of a rod and/or it may be arrangedon a housing edge which connects a horizontal top side 9 and an uprightfront side 10 of the device housing portion 4. In other words, thehandle 7 may lie parallel to an intersection of a plane parallel to thetop side 9 with a plane parallel to the front side 10. Here, the devicehousing portion 4 may comprise a recess 18 around the handle 7 such thatthe hand 20 is able to grasp the handle 7 with index finger, middlefinger, ring finger, and little finger. However, the necessary clearspace for grasping the handle 7 may also be obtained by e.g. an arcuateor protruding contour of the handle 7, and so the aforementioned recess18 is not necessary. It is possible to mention that the terms“horizontal”, “standing” and “upright” should be understood to meanrelative position specifications, i.e. these may relate to a relativereference system of the device or to the Earth's reference system.

As shown in FIGS. 3 and 4, the unit 6 made of fingerprint sensor 21 andfirst electrode 23 may likewise be assigned to the handle 7, said sensorbeing arranged at a distance from an end of the handle 7 bothtransversely in relation to the longitudinal axis 15 of the handle 7 andin the direction of the aforementioned longitudinal axis 15. Inparticular, the aforementioned unit 6 with the fingerprint sensor 21 maybe arranged on the upright front side 10 of the device housing portion4, wherein the unit 6 or the fingerprint sensor 21 and the firstelectrode 23 may be arranged at a slight distance, preferably a meanthumb length, preferably 60 to 80 mm, below the handle 7 and away fromthe handle 7 to one side—to the left in accordance with FIGS. 3 and4—such that a thumb 12, which is not grasping the handle 7 but spreadaway from the handle 7, comes to rest on the aforementioned unit 6 madeof fingerprint sensor 21 and first electrode 23 in the case of anatural, intuitive thumb position. As a result of a suitable distancebetween the hand bearing surface/handle 7 and the unit 6 (or thefingerprint sensor 21), it is optionally advantageously possible torealize an indirect age restriction to the extent that e.g. children oradolescents are no longer able to place the thumb 12 onto the unit 6 orthe first electrode 23 or the fingerprint sensor 23 when grasping thehandle 7 because the distance is too large. Consequently, the e.g.device cannot be put into operation as a result thereof.

FIG. 5 shows the handle 7 from FIG. 3 or 4 from a rear view. As shown byFIG. 5 in particular, the at least second electrode 8 is e.g. attachedto a rear side of the handle 7 when, as it were, the hand bearingsurface 7 is configured as a handle. As a result, when the handle 7 isgrasped by index finger, middle finger, ring finger, and little fingerof the hand 20, at least one of these fingers is placed on the at leastsecond electrode 8. A thumb 12 which does not grasp the handle 7 and isspread away intuitively comes to rest on the unit 6 made of fingerprintsensor 21 and first electrode 23, as a result of which the fingerprintof the thumb 12 can be read or detected very easily by the fingerprintsensor 21 of the unit 6, for example by optical or electrical—usuallycapacitive—means.

The distance of the unit 6 made of fingerprint sensor 21 and firstelectrode 23 from the aforementioned handle 7 transversely to the handlelongitudinal axis 15 and/or in the direction of the handle longitudinalaxis 15 from the handle end (downward and to the left in respect of thehandle 7 in accordance with FIG. 4) advantageously equals the distanceof the thumb tip from the root joint of the index finger, i.e. the usualthumb range when the thumb is spread away, and may be a few centimeters.

As shown in FIG. 3, the unit 6 made of fingerprint sensor 21 and firstelectrode 23, with a principal axis 13, may be arranged tilted in anacute-angled manner about a angle a in relation to the handlelongitudinal axis 15, wherein the aforementioned angle a may be e.g. 5to 35 degrees, in particular dimensioned in such a way that theprincipal axis 13 corresponds to the thumb longitudinal axis in the caseof a natural thumb position. Such an arrangement or acute-angledinclined alignment in relation to the principal axis 13 of the unit 6made of fingerprint sensor 21 and first electrode 23 is alsoadvantageous in the case of a hand bearing surface 7 not beingconfigured as a handle—as depicted in an exemplary manner in FIG. 2.

As an alternative or in addition to the twist of the unit 6 made offingerprint sensor 21 and first electrode 23 in the plane of the frontside 10—i.e. about an axis perpendicular to the front side 10—as seen inFIG. 4, the unit 6 made of fingerprint sensor 21 and first electrode 23may be tilted out of the front side 10 with its bearing surface 21 orthe principal axis 13 thereof. This tilt in respect of an upright tiltaxis 17 parallel to a front side is shown by the acute angle β, visiblein FIG. 2, in relation to the handle longitudinal axis 15. This tilt maylikewise lie in the range from approximately two (2) to 35 degrees.Alternatively, or additionally, the unit 6 made of fingerprint sensor 21and first electrode 23 may also be tilted with the bearing surfacethereof about a horizontal tilt axis 16 in relation to the devicehousing front side 9 or the handle longitudinal axis 15.

The unit 6 made of fingerprint sensor 21 and first electrode 23 isadvantageously not rigidly fastened in terms of the alignment thereof inrespect of the handle 7 or the hand bearing surface 7 but insteadmounted in a rotatable or tiltable manner. A rotatability or tiltabilitymay in this case be provided in respect of one, some or all of theaforementioned tilt axes 14, 16 and 17, wherein the tiltability may bedimensioned in such a way that the unit 6 made of fingerprint sensor 21and first electrode 23 is able to be brought into various rotational ortilt positions, in which it then keeps its position independently or ina self-locking manner, or else in which it can be fixed by fixationmeans. Alternatively, or additionally, a restoration into a neutralinitial position, for example by means of spring means assigned to thetilt axes, is also possible.

In a further, advantageous configuration of the invention, it ispossible, for example, for a unit 6 made of fingerprint sensor 21 andfirst electrode 23 to be attached symmetrically in relation to a centralaxis of the hand bearing surface 7 in each case in order to be able touse the arrangement in an equally well fitting manner for the left handand the right hand. By way of example, in the case of a hand bearingsurface 7 embodied as a horizontal handle, one unit 6 made offingerprint sensor 21 and first electrode 23 may be attached on theleft-hand side and a further unit 6 made of fingerprint sensor 21 andfirst electrode 23 may be attached on the right-hand side, in each caseat a distance from said handle 7 and in the vicinity thereof.

However, alternatively, a hand bearing surface 7, in each case adaptedaccordingly to the respective hand, may be arranged symmetrically inrelation to a central axis 11 of the unit 6 made of fingerprint sensor21 and first electrode 23. That is to say, a first hand bearing surface7 may be used with e.g. the left hand. A hand bearing surface 7 arrangedmirrored on the central axis 11 of the unit 6 made of fingerprint sensor21 and first electrode 23 may for example be used by the right hand.When the index finger, middle finger, ring finger, and little finger areplaced onto the respective hand bearing surface 7, the thumb of therespective hand 20 is intuitively or automatically placed onto the unit6 made of fingerprint sensor 21 and first electrode 23.

The unit 6 made of fingerprint sensor 21 and first electrode 23, and theaforementioned hand bearing surface 7 with the at least second electrode8, and also the measurement unit 25 may be arranged directly on/in thedevice housing of the gaming machine or the main device. In analternative development of the invention, the device having the unit 6made of fingerprint sensor and first electrode, and the hand bearingsurface 7 may however also be embodied as a separate input device inwhich, likewise, e.g. the measurement unit 25 is arranged and which hasan interface for connection to the main device e.g. in the form of agaming machine or a PC. This interface may be a wired parallel or serialinterface, for example in the form of a USB interface or an RS-232interface, or else it may be an interface working on wirelessprinciples, for example in the form of a WLAN interface or Bluetoothinterface or IrDA interface operating on the basis of infrared signals,or a combination of these interfaces.

As shown schematically in FIGS. 6 and 7, the invention may furthermorebe used e.g. in a mobile, battery-operated, accumulator-operated device24 (cellular telephone, smartphone, handheld device, PDA, games console,tablet) for the purposes of identifying fingerprints.

Here, the unit 6 made of fingerprint sensor 21 and first electrode 23 isarranged or integrated in an input means—e.g. an operating button foractivating a display 22 or the electronics of the mobile device 24.Here, the hand bearing surface 7 with the at least one second electrode8 may—as depicted in e.g. FIG. 7—be provided on a side edge of themobile device 24. Alternatively, or additionally, the hand bearingsurface 7 with the at least second electrode 8 or further electrodes 8may—as shown in an exemplary manner in FIG. 6—be arranged on a rear sideof the mobile device 24. When the mobile device 24 is grasped with thehand 20, e.g. the thumb 12 comes to rest on the input means and hence onthe unit 6 made of fingerprint sensor 21 and first electrode 23, whilethe remaining fingers of the hand 20 are placed on the hand bearingsurface 7 and hence the at least second electrode 8 is contacted by atleast one of the remaining fingers of the hand 20. When applying theinvention in a mobile device such as e.g. a smartphone or tablet PC, themeasurement unit 25 may, for example, be installed or integrated intothis device.

Alternatively, or additionally, the hand bearing surface 7 or the atleast second electrode 8 may also be attached in a protective sleeve forthe mobile device 24 or a through-contact to the hand bearing surface 7or to the at least second electrode 8 may be provided in the protectivesleeve. However, it is also possible for the protective sleeve for themobile device 24 to have a corresponding cutout so that the fingers maybe placed on the at least one second electrode 8. Ideally, a user of themobile device 24 need not take the latter out of the protective sleeveor need not remove the protective sleeve for identification purposes.

FIG. 8 once again shows the arrangement for identifying fingerprints ina schematic form as a block diagram, and an exemplary sequence of amethod for identifying fingerprints with the arrangement. As alreadydescribed on the basis of the preceding FIGS. 2 to 7, the arrangementhas a unit 6 consisting of a fingerprint sensor 21 and a first electrode23. This unit 6 made of fingerprint sensor 21 and first electrode 23 isassigned to a hand bearing surface 7 with at least one second electrode8 or arranged at a distance from said hand bearing surface 7 in thevicinity thereof. Alternatively, instead of the first electrode 23, thefingerprint sensor 21 may form a unit 6 with the at least secondelectrode 8, which is assigned to the hand bearing surface 7, or thesecond electrode 8 has a further fingerprint sensor 21 in addition tothe first electrode 23. Furthermore, the arrangement comprises ameasurement unit 25 for applying and evaluating electrical signals,which are able to be applied and detected between the first electrode 23and the at least second electrode 8.

By way of example, if index finger, middle finger, ring finger and/orlittle finger of a hand 20 are placed onto the hand bearing surface 7,the at least second electrode 8 is contacted by one of these fingers.However, further second electrodes 8 may additionally be provided in thehand bearing surface 7 for a further finger or for a plurality offingers or for all applied fingers of the hand 20. The assignment of thehand bearing surface 7 with the at least second electrode 8 and thefirst electrode 23, or the unit 6 made of fingerprint sensor 21 andfirst electrode 23, is configured in such a way that, when index finger,middle finger, ring finger and/or little finger of the hand 20 areapplied, the thumb 12 of this hand 20 comes to rest in an intuitive andautomatic manner on the unit 6 made of fingerprint sensor 21 and firstelectrode 23. That is to say, the thumb 12 of the hand 20 is placed ontothe unit 6 made of fingerprint sensor 21 and first electrode 23 and theremaining fingers of the hand 20 are placed on the hand bearing surfacewith at least one second electrode 8.

In a first method step 31, the fingerprint sensor 21 of the unit 6detects a fingerprint of the applied thumb 12, e.g. by optical orelectrical (usually capacitive) means. To this end, it is possible, forexample, for an illumination apparatus to be activated for an imagedetection and for, the fingerprint by the fingerprint detectionapparatus, at least one region of the applied thumb to be detected as afingerprint image by a detector. Alternatively, the fingerprint sensor21 may be assigned to the at least second electrode 8; then, forexample, a print of a different finger is detected in the first methodstep 31 instead of a thumbprint, said different finger being applied tothe at least second electrode 8 and consequently to the fingerprintsensor assigned to the at least second electrode 8. The detectedfingerprint image can then e.g. be buffer stored in the measurement unit25 and, in a subsequent method step, be forwarded with further data, orimmediately, to an overarching system—e.g. a computer system for qualitycontrol and/or evaluation. If the fingerprint image is lacking quality,for example if an image contrast is too low, a region of the fingerprintis too small, the number of minutiae points do not suffice, etc., it ispossible, for example, for a second fingerprint image to be detected bythe fingerprint sensor 21.

As a further alternative embodiment of the invention, it is alsopossible for the second electrode 8 to have a further fingerprint sensor21, in addition to the unit 6 made of first electrode 23 and fingerprintsensor 21. Then, e.g. in the first method step 31, it is also possibleto detect a print of a further finger of the hand 20—such as e.g. theindex finger—by means of the further fingerprint sensor 21, which isassigned to the second electrode 8, in addition to a thumbprint which isdetected by the unit 6 made of first electrode 23 and fingerprint sensor21.

If an acceptable image quality of the detected fingerprint wasdetermined, electrical signals are transferred or fed by the measurementunit 25 to the hand 20, applied by way of the thumb 21 and the remainingfingers, by way of the first electrode 23 and the at least secondelectrode 8 in a second method step 32. By way of example, voltagesignals with variable amplitude and/or frequency may be used aselectrical signals. These fed signals are guided via the fingers or thehand 20 applied to the respective electrodes, for example from themeasurement unit 25 via the first electrode 23, via a connection 26,which is formed by the hand 20, and via the at least second electrode 8back to the measurement unit 25, or in the opposite direction.

In a third method step 33, the electrical signals, which are modified bythe hand 20 applied to the first electrode 23 and at least one secondelectrode 8 (e.g. by periodic voltage changes of the pulse, etc.), aredetected by the measurement unit 25. Hence, the first electrode 23 andthe at least one second electrode 8 act as transmission and receptionunits for the electrical signals. Then, the detected, modifiedelectrical signals are processed further and evaluated in themeasurement unit 25. Thus, an impedance measurement of a hand path 26from the thumb 12 to one or more of the fingers may be carried out e.g.on the basis of a sequence of electrical signals which are transferredby way of the first electrode 23 and the at least one second electrode8, with the measurement result then e.g. being compared to apredetermined measurement result range. However, it is also possibleonly to compare the detected electrical signals from the measurementunit 25 with a predetermined range, e.g. a characteristic measurementrange for the determination of life. If the detected, electrical signalslie within a threshold, e.g. for a specific person who e.g. was recordedduring a registration, or within a general predetermined threshold forhumans, the detected finger may be accepted as real. That is to say, thefingerprint detected in the first method step 31 originates from aliving person with a very high probability. If deviations of thedetected, electrical signals from the predetermined range are determinedin the third method step 33, the detected finger may e.g. be declaredfake (e.g. artificial or severed finger, film applied to the finger withfake fingerprint, etc.) and access, entry, etc. may be refused to theassociated person.

By way of example, the measurement unit 25 can generate an imitationvalue on the basis of the comparison of the detected, modifiedelectrical signals with the predetermined range. By way of example, thisimitation value can assign a probability of a fake to the detectedfinger. By way of example, a low value of the imitation value may meanthat the probability of a fake is low; a high value of the imitationvalue may mean the probability of a fake is high.

This imitation value and/or the detected, modified electrical signalsmay be forwarded in a fourth method step 34, for example together withthe fingerprint image detected by the fingerprint sensor 21, to theoverarching system for an evaluation and analysis. The fingerprint imagemay be checked in terms of the quality thereof—as explained in the firstmethod step 31. The detected, modified electrical signals and/or theimitation value may be used for the detection of life or for anevaluation as to whether the applied, detected finger is real (i.e.originates from a living person) or a fake. If no fake is determined thedetected fingerprint image can be evaluated and the person can beidentified.

In an advantageous development of the arrangement or of the method foridentifying fingerprints, at least the second electrode 8 may beembodied as a force-effect detection unit. Here, the electrical signalsin the second method step 32 are only applied to the first electrode 23and the at least second electrode 8 by the measurement unit 25 if forceis exerted by the corresponding finger, with the force needing to obtaina predetermined threshold. That is to say, an electrical circuit fromthe measurement unit 25 via the first electrode 23, the applied hand 20or via the connection 26 formed thereby, the at least second electrode 8to the measurement unit 25 (or in the reverse direction) is, as it were,closed when the predetermined threshold is reached. Here, theforce-effect detection unit in the at least second electrode 8 has thefunction of a switch which is closed in the case of a sufficiently largeforce (=a force reaching or exceeding the threshold).

Alternatively, the electrical signals can already be applied to theelectrodes 8, 23 when the respective electrodes 8, 23 are contacted bythe respective fingers—i.e. thumb 12 and one of the other fingers—, i.e.as if the at least second electrode 8 were not embodied as aforce-effect detection unit. However, the detection and evaluation ofthe modified, electrical signals in accordance with the third methodstep 33 is only started once the predetermined threshold for the exertedforce on the force-effect detection unit is reached or exceeded. That isto say, the at least second electrode 8 or the force-effect detectionunit acts like a switch, by means of which tapping or evaluating of themodified, electrical signals by the measurement unit 25 is started if anappropriate force is exerted.

Optionally, the unit 6 made of fingerprint sensor 21 and first electrode23 may also be configured as a force-effect detection unit.

By way of example, the force-effect detection unit may be based on aspring-force restoration and/or embodied as a pressure switch. Then, aspring-pressure threshold is advantageously used as a threshold for theforce-effect detection unit. Alternatively, use can be made of e.g. aforce-measuring, electrical resistor such as e.g. a so-calledforce-sensing resistor (FSR). The force-effect detection unit is thenembodied e.g. as a pressure sensor, in which use is made of a passivecomponent for processing a variable, electrical resistance, wherein theresistance value of this component is modified or reduced withincreasing action of force on the sensor.

The electrical signals are only applied to, or tapped or evaluated from,the electrodes 8, 23 by the measurement unit 25 once the correspondingthreshold—e.g. a pressure threshold or threshold of the electricalresistance—of the force-effect detection unit is reached or exceeded.Furthermore, an indication apparatus such as e.g. an LED, etc. may becoupled to the force-effect detection unit. This indication apparatuscan indicate to the user, e.g. by lighting up, changing color, etc.,that the corresponding threshold of the force-effect detection unit, andhence for an identification of the fingerprint, has been reached andfurther application of force on the force-effect detection unit is nolonger necessary.

The security in relation to manipulation may be additionally increasedin a simple manner by the configuration of at least the one secondelectrode 8 as a force-effect unit. This is because a correspondingaction of force is not readily realizable with an imitated, artificialfinger (e.g. rubber finger) or an imitated hand (e.g. rubber hand), ontowhich fingerprints were applied for manipulation purposes.

The invention claimed is:
 1. An arrangement for identifyingfingerprints, comprising: at least one fingerprint sensor to detect atleast one fingerprint; at least two electrodes; and a controller toapply and evaluate at least one electrical signal between the twoelectrodes, wherein a first electrode is spaced apart from an at leastone second electrode, wherein the at least one second electrode isattached to a hand bearing surface, wherein the first electrode isconfigured for the placement of a thumb of a hand and the at least onesecond electrode is configured for the placement of at least one of anindex finger, middle finger, ring finger, and little finger of the handwherein the at least one fingerprint sensor is attached to the at leastone of the first electrode and the at least one second electrode,wherein the at least one electrical signal is modified by passingthrough the hand via the first electrode and at least one secondelectrode, and wherein an identification result can be established bythe evaluation of the detected fingerprint and the evaluation of the atleast one modified electrical signal.
 2. The arrangement as claimed inclaim 1, wherein the hand bearing surface is configured as a handle,which is able to be grasped by the index finger and/or middle fingerand/or ring finger and/or little finger of the hand.
 3. The arrangementas claimed in claim 1, wherein the hand bearing surface is provided on adevice housing side which is arranged in an inclined manner in relationto a further device housing side, wherein the unit made of fingerprintsensor and first electrode is attached to the further device housingside.
 4. The arrangement as claimed in claim 3, wherein the two devicehousing sides are aligned at approximately right angles in relation toone another.
 5. The arrangement as claimed in claim 1, wherein the unitmade of fingerprint sensor and first electrode is movably arrangedrelative to the hand bearing surface, in particular mounted in arotatable and/or tiltable and/or translationally displaceable manner. 6.The arrangement as claimed in claim 1, wherein the first electrode andthe at least one second electrode are produced from a light-transmissivematerial.
 7. The arrangement as claimed in claim 1, wherein the at leastsecond electrode is configured as a force-effect detection unit, whereinthe electrical signals are only able to be applied to the respectiveelectrode, and/or tapped/evaluated, by a measurement unit when force isexerted by the corresponding finger onto the force-effect detectionunit.
 8. The arrangement as claimed in claim 1, wherein the arrangementis employable in a device, in particular in an amusement device orgaming machine, and/or in a mobile device, in particular a smartphone.9. A method for identifying fingerprints using an arrangement whichcomprises: detecting at least one fingerprint by at least onefingerprint sensor; evaluating at least one electrical signal from acontroller that has been modified by passing through a hand via a firstelectrode, configured for placement of a thumb of the hand, and at leastone second electrode, configured for placement of at least one of anindex finger, middle finger, ring finger, and little finger of the hand;and establishing an identification result by the evaluation of thedetected fingerprint and the evaluation of the at least one modifiedsignal.
 10. The method as claimed in claim 9, wherein a detectedfingerprint is forwarded to an overarching system for evaluation andanalysis.
 11. The method as claimed in claim 9, wherein the detected,modified electrical signals are compared with a predetermined range by ameasurement unit.
 12. The method as claimed in claim 11, wherein animitation value is generated by the measurement unit on the basis of acomparison with the predetermined range.
 13. The method as claimed inclaim 12, wherein the imitation value is forwarded from the measurementunit to the overarching system for an evaluation.
 14. The method asclaimed in claim 9, wherein voltage signals with variable amplitudeand/or frequency are used as electrical signals.
 15. The method asclaimed in claim 9, wherein the at least one second electrode isembodied as a force-effect detection unit, in that the electricalsignals are only applied to the respective electrode, and/ortapped/evaluated, by the measurement unit when a predetermined thresholdfor the exerted force is reached or exceeded in the case of forceexerted by the corresponding finger onto the force-effect detectionunit.
 16. The method as claimed in claim 15, wherein a pressurethreshold or threshold for electrical resistance is predetermined as athreshold for the force-effect detection unit.
 17. The method as claimedin claim 9, wherein the at least one fingerprint sensor is attached toat least one of the first electrode and the at least one secondelectrode.
 18. An arrangement for identifying fingerprints, comprising:at least two electrodes; and a controller to apply and evaluate at leastone electrical signal between the two electrodes, wherein a firstelectrode is spaced apart from an at least one second electrode, whereinthe at least one second electrode is attached to a hand bearing surface,wherein the first electrode is configured for the placement of a thumbof a hand and the at least one second electrode is configured for theplacement of at least one of an index finger, middle finger, ringfinger, and little finger of the hand, wherein the at least oneelectrical signal is modified by passing through the hand via the firstelectrode and at least one second electrode, wherein the at least onesecond electrode is configured as a force-effect detection unit, whereinthe electrical signals are only able to be applied to the respectiveelectrode when a force greater than a predetermined threshold is appliedto the force-effect detection unit, and wherein an identification resultcan be established by the evaluation of the detected fingerprint and theevaluation of the at least one modified electrical signal.
 19. Thearrangement as claimed in claim 18, wherein the hand bearing surface isconfigured as a handle, which is able to be grasped by the index fingerand/or middle finger and/or ring finger and/or little finger of thehand.
 20. The arrangement as claimed in claim 18, wherein the handbearing surface is provided on a device housing side which is arrangedin an inclined manner in relation to a further device housing side,wherein the unit made of fingerprint sensor and first electrode isattached to the further device housing side.